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Injuries Related to Positioning in Anesthesia
Irene P. Osborn, MD
Mount Sinai Medical Center
This lecture will discuss (from head to toe) the considerations and complications
of patient positioning under anesthesia. Perioperative nerve injury continues to
be a significant source of injury for the anesthetized patient. Meticulous care
must be taken while moving a patient into the desired surgical position. An
understanding of anatomy and physiologic changes is important in prevention.
Incidence of perioperative nerve injuries:
15% of ASA closed claims in 1990
Ulnar neuropathy 34%
-75% male
Bracheal plexus 23%
Lumbosacral 16%
Most Frequent Claims for Nerve Injury by Gender
Nerve
# Claims % of 445 % Female % Male
All nerve damage claims 445
100%
49%
51%
Ulnar Nerve
113
25%
21%
79%
Brachial Plexus
83
19%
57%
43%
Spinal Cord
73
16%
49%
51%
Nerve Root
67
15%
70%
30%
Sciatic Nerve
23
5%
61%
39%
Lumbosacral
Problems with positions for optimal surgical exposure:
1) May evoke undesirable physiological changes
-Impairment of venous return, V/Q mismatch
2) Anesthesia may blunt normal protection mechanisms
-Loss of sympathetic tone, limbs placed in unnatural positions
Causes of nerve injury:
•Section
•Compression
•Traction
•Ischemia
* Type of surgery (sternotomy)
* Prolonged placement (> 4 hrs lithotomy)
* Prolonged tourniquet (>2 hrs)
* Congenital anomalies (cervical rib)
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Neurovascular compromise:
•Compression or stretching of intraneural vasa nervorum – neural ischemia
•Nerve has a long or superficial course between two points of fixation
•Stretching and compression combined – worst
•Tissue edema from IV fluid may contribute to neurovascular compression
Coexisting medical problems which may contribute to injury:
•Diabetes mellitus
•Alcohol abuse
•Vitamin deficiency
•Coagulopathy/ Hypothermia
Uremia
Polycythemia vera
Acromegaly
Hypothyroidism
Equipment malfunction is also a cause of problems, specifically tourniquets,
blood pressure cuffs, infusion pumps or armboards.
Head
Pressure alopecia
- prolonged compression of hair follicles
- hypothermia/hypotension increase risk
- often begins 3 days post op
- prevent with padding, frequent turning of head
Cervical hyperextension- nerve root injury, spinal cord trauma
Face
Supraorbital nerve compression (circuit, ETT)
Pressure from facemask or strap placement, position
Upper extremity neuropathies
Stretch-induced neuropathy of the brachial
plexus and median nerve remains a
frequently preventable complication.
Diagnosis:
Pain, numbness, decreased movement noted immediately postoperatively to
48 hours post surgery.
Prevention of brachial plexus injuries:
- avoid abduction of the arm > 90 degrees
- minimize combination of abduction, external rotation and dorsal extension
- avoid downward pressure on the head of the humerus
- avoid placing humerus behind the plane of the body
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Ulnar nerve
The ulnar nerve can be compressed against the posterior aspect of the
medial epicondyle of the humerus. Compression may result from the sharp
edge of the OR table, stretching-induced when the arm is abducted between
60 and 90 degrees on an arm board in the supine or prone position.
Median nerve injury:
•Avoid extreme wrist dorsiflexion
•Avoid IV infusions in antecubital fossa
Thoracic outlet syndrome: N – very superficial
Compression of bracheal plexus
and subclavian vessels near first rib and
clavicle, plexus pain and paresthesias
Lower extremity neuropathies
•Sciatic N – Long and fixed between two points
•Peroneal N – very superficial
•Tibial – compressed in popliteal fossa
•Saphenous – superficial at medial upper tibia
Common peroneal nerve:
*Branch of sciatic
*Most frequently damaged LE nerve
*Compression of fibula head and metal support frame
*Foot drop, loss of dorsal extension
Potential obstetrical injury
 sciatic nerve trauma- lithotomy
 hyperflexion of back
 compression during vaginal delivery
 rotation of femur in stirrups
Nerve Complications of Sitting position:
*Excessive neck flexion- spinal cord ischemia
*Sciatic nerve injury- excessive LE extension
*Airway edema- tongue swelling
Prone position:
Brachial plexus may be stretched (arms not > 90 degrees)
No undue neck extension or flexion
Eye/nose damage from pressure
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Flexion of hips/knees
Ischemic Optic Neuropathy- most alarming and devastating complication!
Managing Perioperative Nerve Injuries:
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


Determine if sensory or motor (sensory is usually transient)
Avoid stretch and recheck in 5 days
Contact patient frequently
If persistent after 5 days- neurology consult
 Nerve conduction studies
 EMG
 If motor, do consult immediately
Conclusion:
Components of Safe Positioning
KnowledgePlanningTeamworkHousekeeping-
understanding general principles of operative positioning
understand positioning concerns of anesthesia and surgery
sufficient personnel for positioning
equipment that works, proper devices
Don’t forget to document padding and attention to patient positioning.
References:
1. Practice Advisory for the Prevention of Perioperative Peripheral
Neuropathies. Anesthesiology 2000;92:1168-82.
2. Coppieters MW, Van De Velde M, Stappaerts KH. Positioning in
anesthesiology. Toward a better understanding of stretch-indued
perioperative neuropathies. Anesthesiology 2002;97:75-81.
3. Britt BA, Joy N, Mackay MB. Anesthesia-Related Trauma Caused by
Patient Malpositioning in Complications in Anesthesiology Gravenstein N,
Kirby RR (eds).
4. Kroll D. Nerve injury associated with anesthesia. Anesthesiology.
1990;73:202.
5. Cheng MA, Todorof A, et al. The effect of prone positioning on intraocular
pressure in anesthetized patients. Anesthesiology 2001 Dec;95(6):1351-5.